Vehicles operating in an autonomous mode (e.g., driverless) can relieve occupants, especially the driver, from some driving-related responsibilities. When operating in an autonomous mode, the vehicle can navigate to various locations using onboard sensors, allowing the vehicle to travel with minimal human interaction or in some cases without any passengers.
Keeping a distance between an autonomous driving vehicle (ADV) and another vehicle following the ADV is important when driving the ADV for safety reasons, especially, when the ADV is about to rapidly slow down such as an emergency stop situation. While sudden stop during driving is rare and usually used to avoid accidents, it is very dangerous and may cause other accidents, most likely from the following vehicles.